One-way valve



FIG. 1 is a perspective view, from one side, of a one-way valve showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is right side view thereof.

The broken line showing in the figure drawings are included for the purpose of illustration and form no part of the claimed design. 

CLAIM I claim the ornamental design for a one-way valve, as shown and described. 